L-methionine 

L-methionine (L-Met) is an essential sulfur-containing amino acid in daily diet, the first limiting amino acid in poultry and aqua, the second or third limiting amino acid in swine, which possesses both high nutritional value and important physiological functions such as antioxidant functions. Whats more, L-Met is closely related to the immune function of livestock, which has effects not only on the development of immune organs, but also on the specific and nonspecific immune function of organisms.

Effects of L-methionine on immunity

1. Improving Immune System

1) Efficient for the T-cell proliferation and differentiation
L-Met plays a key role in catabolism of the immune system.
L-Met and L-Met-derived metabolites protect host immune
cells through antioxidant mechanism and ensure the expression
and stability of the T-cell lineage.

2) Immune response of L-Met metabolic products
L-Met can serve as substrates for generating compounds involved in the immune response, such as glutathione (GSH), cysteine, H2S (Litvak et al., 2013). For example, GSH, which has anti-oxidative defense, is important for the activity of polymorphonuclear neutrophils and dendritic cell functions. Moreover, GSH prevents cellular damage from ROS (reactive
oxygen species) such as free radicals, peroxides and heavy metals.

2. High Anti-oxidative Defense →Enhance Gut Health

1) Healthier duodenum morphology
L-Met has beneficial effects on villus development in association with the increased levels of GSH and TAC (Total Antioxidant Capacity) and reduced protein oxidation in duodenum.

2) L-Met: better antioxidant in piglets
Table is the result of GSH, TAC, MDA (Malondialdehyde), and protein carbonyl concentrations in duodenum and liver of pigs fed diets supplemented with either L-Met or DL-Met.
⇒ Diet supplemented with L-Met has higher antioxidant activity in liver and jejunum.

*References are available on request